Water Rocket Forum

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A water rocket is a type of model rocket using water as its reaction mass. The pressure vessel (the engine of the rocket) is constructed from thin plastic or other non metallic materials (usually a used plastic soft drink bottle) weighing 1,500 grams or less. The water is forced out by compressed air. It is an example of Newton's third law of motion.

arjan wrote:I was wondering if multi stage rockets are allowed in the altitude challenge?

Arjan

Hi Arjan,

Yes there are no rules against launching a multi-stage rocket in the Altitude Challenge Competition. Just be aware that the weight limit of 1500 grams (empty and flight ready) still applies no matter how many stages are used. Also the rocket needs to be constructed from ordinary materials (no epoxy-composite wraps) This competition was designed to keep costs low).

WRA2 wrote: Also the rocket needs to be constructed from ordinary materials (no epoxy-composite wraps) This competition was designed to keep costs low).

I can't find that in the rules, or am I just reading over it?

I was planning to build a sustainer out of glassfibre because of the high costs of ftc in my country.
I pay 10 euros for 1 piece of t8 150cm ftc and that's without shippingcosts of also 10 euros.

Arjan

Hi Arjan,

You may use fiberglass/epoxy for your sustainer if you choose but the maximum launch pressure allowed is 200PSI. This competition was designed to be lower cost than the Single and Multi-stage competitions and the pressure limit was designed in the keep material costs low. Otherwise the competition would be too similar to the others and big budget teams could outspend the competition.

Also remember that your boosters must have some kind of recovery system that limits the descent rate.

Good Luck!

Lisa Walker,Forum Administrator. The Water Rocket Achievement World Record Association

I was aware of the maximum launch pressure of 200 psi.
The lower costs are the reason why I want to build a rocket for this competition.
I have to do a lot of testing first but at least I can go on with my plans.

I was aware of the maximum launch pressure of 200 psi.
The lower costs are the reason why I want to build a rocket for this competition.
I have to do a lot of testing first but at least I can go on with my plans.

Arjan

What I meant to say is that it probably isn't recommended that you use composite wraps as a method of reinforcement for your pressure vessel. The reason the membership settled upon the 200 PSI limit was that it would exclude most wrapped rockets as being too heavy for the maximum allowed pressure and that the wrapping would be impractical but members still had the option to use the material for parts of their rockets. You might want to consider a lighter method of reinforcement for your sustainer such as fiberglass tape.

Lisa Walker,Forum Administrator. The Water Rocket Achievement World Record Association